The molecular details of the synthesis, structure, and some functional aspects of avian tumor virus DNA in infected quail tumor cell line will be investigated. Attempts will be made to understand the mechanism of poly(A) removal from the 3'-end of genomic RNA during reverse transcription. Whether the polyA is removed as a stretch or degraded by an exonucleolytic process will be determined. The events leading to the initiation and elongation of plus strand will be explored by using restriction enzyme fragments which can be obtained from cloned ASV genome. These restrictions fragments will be labeled either by nick translation using E. coli DNA polymerase I or by end labeling using T4 polynucleotide kinase. One of the fascinating aspects of RNA tumor virus research concerns the mechanism of viral RNA transcription by eukaryotic RNA polymerase II. We will attempt to understand the structural elements in the ASV DNA which determine the selective and preferential transcription of its genome by the host RNA polymerase II. We wish to identify and isolate a possible promoter and use it as a specific reagent to transcribe avian and other eukaryote genes in order to understand its uniqueness. This will be accomplished by direct polymerase binding studies, by injecting cloned ASV DNA into xenopus oocytes, by co-transferring the putative promoter containing fragment with thymidine kinase gene and by direct in vitro transcription using cell free lysate systems.